Calcium plays an important role in blood coagulation, nerve transmission, muscle contraction, and heart function. Protection against high blood pressure, colon cancer, and the degenerative bone disease known as osteoporosis have been attributed to calcium. Approximately one percent of the body's calcium circulates in the blood and the rest is present in bones and teeth. The U.S. Recommended Daily Allowance (R.D.A.) of calcium is 1000 mg for adults and children 12 or more years of age. The R.D.A for pregnant and lactating women is 1200 mg. However, the average calcium intake is only about one-third of the required daily allowance. If dietary sources of calcium do not provide sufficient amounts of calcium to the blood, calcium is depleted from the bones to compensate for the insufficient amounts. Age related bone loss and fracture rates in patients with osteoporosis may be reduced with high dietary intake of calcium.
The ability of different individuals to utilize the calcium in food may vary considerably. For example, a high protein diet may result in about 15% of the dietary calcium being absorbed. A low protein diet may result in only about 5% of the dietary calcium being absorbed. Phytic acid in cereal grains interferes with calcium absorption by forming insoluble calcium phytate in the intestine. Oxalates in foods, such as spinach and rhubarb, may similarly interfere with calcium absorption.
Other intestinal factors that influence the absorption of calcium include pH, the calcium:phosphorus ratio, the presence of free fatty acids which occurs when fat absorption is impaired, and the amount of vitamin D. Generally, the more alkaline the contents of the intestines, the less soluble are the calcium salts. Also, a high calcium:phosphorus ratio favors the formation of tricalcium phosphate rather than the more soluble, better absorbed forms. If either calcium or phosphorus is taken in excess, excretion of the other is increased. The optimal ratio is 1:1 when the intake of vitamin D is adequate. On the other hand, vitamin D promotes the absorption of calcium from the intestine.
Although milk has been a major source of calcium for infants and young children, many teenagers and adult Americans are consuming lesser amounts of it. The calcium content of milk and other beverages may be increased to facilitate meeting of the U.S. R.D.A. for calcium.
For example, calcium enrichment or fortification of milk is disclosed in U.S. Pat. Nos. 2,871,123, 4,701,329, 4,840,814, and 4,851,243. In U.S. Pat. No. 2,871,123 calcium carbonate is used as a calcium source in the production of a canned calcium-enriched concentrated milk product for dilution to make infant formula. Carrageenan gum is used for suspension of the calcium carbonate. U.S. Pat. Nos. 4,701,329 and 4,851,243 disclose the production of calcium-enriched and phosphorus- enriched fortified milk by the addition of tri-basic calcium phosphate, carrageenan and guar gum to fresh milk, effecting hydration of the gums, and assuring uniform distribution of the added materials in the milk. U.S. Pat. No. 4,840,814, discloses the preparation of calcium-enriched milk or toned milk by adding a water soluble calcium salt of an organic acid to thermally sterilized milk or toned milk, and adjusting the pH value of the obtained mixture to 6.6 or above.
Beverages and beverage concentrates nutritionally supplemented with solubilized calcium are disclosed in U.S. Pat. Nos. 4,737,375 and 4,740,380. In U.S. Pat. No. 4,737,375 the beverages and concentrates are substantially free of a sugar alcohol and contain specified levels of total edible acids selected from mixtures of citric, malic and phosphoric acid. U.S. Pat. No. 4,740,380 discloses a clear, calcium-fortified aqueous acidic beverage. The beverage comprises an aqueous solution of an organic calcium compound such as calcium gluconate at a pH of about 4 and below wherein the calcium compound content does not exceed the solubility limit of the compound in water. An inorganic calcium salt can be used alone or in combination with an organic calcium compound to form an acidic beverage provided the pH is adjusted with an organic acid.
However, when incorporating calcium into liquids, the source of calcium, usually an inorganic salt in finely divided form, tends to settle out upon extended storage. Also, the use of soluble sources of calcium or even the use of suspended sources of calcium tends to result in off flavors, adverse appearance, and undesirable increases in viscosity. Generally, the more soluble the salt or the more finely divided it is so as to improve suspendability, the quicker or more easily its taste will be detected. Also, solubilization of the calcium increases the likelihood of it being complexed with or interacting with other components of the beverage or of other foods consumed with it. The complexation or interaction of the calcium may result in it being less susceptible to absorption into the blood.
Calcium enrichment of other foods such as bean curd, yogurt, and cereal grains is disclosed in U.S. Pat. Nos. 4,676,583, 4,784,871, and 4,765,996, respectively. U.S. Pat. No. 4,676,583 discloses the production of an aseptic calcium-enriched soy bean curd by adding a calcium hydroxide-sucrose complex as coagulant to the soy bean milk, sterilizing the resulting mixture by heating, adjusting the pH value of the sterilized product to weakly acidic, charging the sterilized product into a container under an aseptic condition and sealing the opening of the container. The calcium hydroxide-sucrose complex is coagulated with the soybean milk by heating. When the calcium hydroxide-sucrose complex used as coagulant is insufficient to provide the required extent of calcium enrichment, calcium lactate may be added in an aseptic atmosphere after the sterilization process at the time of pH adjustment. According to U.S. Pat. No. 4,784,871 a calcium fortified yogurt is produced by adding an acid soluble calcium salt to fruit flavoring which is subsequently combined with a yogurt base. In U.S. Pat. No. 4,765,996 polished rice or barley is enriched with nutrients which are fixed in and on the grain by coating an oil/fat and/or a wax on the grains, coating the same with a hydrophilic emulsifier and further coating them with a starch-based coating agent.
Calcium compounds have been utilized in baked goods, such as crackers, as components of leavening agents, pH adjusters, yeast foods, and for their nutritive value. U.S. Pat. No. 4,196,226 discloses a leavening acid comprising alkali metal aluminum phosphate granules having a calcium rich outer surface for improving flow and dusting properties. The product may be used as a leavening acid in moist doughs, and liquid batters such as pancake batters. U.S. Pat. No. 4,678,672 to Dartey et al discloses the use of calcium and ammonium carbonates and bicarbonates in leavening systems for the production of reduced calorie crackers. Various emulsifiers are disclosed as replacements for fat. Magnesium and/or calcium carbonates are taught as acid-neutralizing constituents in British patent 335,214 for dough or flour compositions which contain persulphates and bromates. Calcium carbonate is disclosed as a bread improver in U.S. Pat. No. 2,970,915. It is also taught as a buffering agent for a liquid yeast brew in U.S. Pat. No. 3,490,916. The dough-up stage addition of calcium carbonate for its nutritive value in the production of reduced fat or no-added fat crackers, is disclosed in U.S. Pat. No. 5,108,764 to Craig. U.S. Pat. Nos. 4,859,473 and 5,066,499 to Arciszewski et al disclose the addition of calcium carbonate to the dough-up stage for its nutritive value in the production of low sodium crackers.
The delivery of dietary calcium using crackers and other low moisture content baked goods as a medium has significant advantages over the use of milk, other dairy products such as yogurt, beverages, tofu, and whole grains. Crackers generally exhibit much longer shelf lives than do dairy products such as milk and yogurt. Settling out of calcium salts from solution or suspension during product storage is not encountered when using crackers as a dietary source of calcium. Also, crackers and other baked goods have broad appeal to many segments of the population. However, commercially available crackers generally provide only up to about 3% of the U.S. R.D.A. of calcium per serving. It has been found that the incorporation of calcium in crackers in amounts to provide more than 10% of the U.S. R.D.A. of 1000 mg calcium per serving results in a hard cracker texture.
Also, reducing the fat content of crackers and other baked goods results in a harder texture as disclosed in copending, commonly assigned U.S. application Ser. No. 08/351,059 for "Tenderized Baked Good Production With Reduced Fat, Low-Fat, Or No Added Fat" filed Nov. 29, 1994 in the names of Ellen L. Zimmerman, Julia M. Carey, Louise Slade, and Harry Levine, which application is incorporated herein by reference in its entirety.
In the preparation of baked goods, fat lubricates and reduces viscosity of the dough. Fat retards starch from swelling, and from gelatinizing (including the second stage of gelatinization known as pasting). It also provides flavor and tenderness to the final product. Methods for making reduced fat, low-fat, or fat-free (no added fat) baked goods must somehow compensate for the multiple functions of fat when reducing or eliminating fat.
In producing crackers on a mass production basis, a cracker dough must be continuously sheetable, and it should preferably be capable of being laminated upon itself. The baked product should be non-brittle, so as to be transferable between conveyor belts and packaging equipment without excessive breakage.
Water can be used to reduce viscosity and to provide adequate lubrication to the dough in the absence of fat, but water cannot be used as the sole means to provide tenderness to the final product. Fat-free crackers made only with water as the fat replacement are flinty and so absorptive as to cause unpleasant dryness in the mouth upon eating.
As disclosed in U.S. Pat. No. 5,108,764 to Craig, et al., a major source of the textural problem in crackers is believed to be excessive gelatinization of starch in crackers made with extra water without adding fat. Excessive gelatinization of starch during baking makes the cracker flinty and very moisture-absorbent. Retention of water in the cracker dough during baking causes excessive gelatinization and the resultant inferior cracker. Thus, when preparing crackers, unlike preparing bread, starch gelatinization is to be limited. For example, in full-fatted crackers, 75% of the starch may be gelatinized. Removal of the fat may result in an increase of gelatinization to 85% or more, with a resultant cardboard-like texture.
In the process of U.S. Pat. No. 5,108,764, the added fat or shortening content of a mass-produced cracker is reduced using water and an enzyme composition that hydrolyses non-cellulosic cell wall polysaccharides. The enzymatic treatment and the amount of water are such so as to avoid excessive gelatinization during baking.
The use of various emulsifier systems to reduce fat in foods is disclosed in International Publication No. WO 91/18514, published Dec. 12, 1991, U.S. Pat. No. 5,254,356 to Busken, U.S. Pat. Nos. 4,678,672 and 4,668,519 to Dartey, et al., U.S. Pat. No. 5,080,921 to Reimer, U.S. Pat. No. 5,082,684 to Fung, U.S. Pat. No. 4,468,408 to Bosco, et al., U.S. Pat. No. 3,919,434 to Tsen, et al., U.S. Pat. No. 5,160,759 to Nomura, et al., and U.S. Pat. No. 5,154,942 to Hirschey, et al.
In embodiments of the present invention, an emulsifier composition is used to provide an unexpectedly soft and tender texture and enhanced flavor to calcium-enriched crackers and other baked products which provide more than 10% of the U.S. R.D.A. of 1000 mg of calcium per serving. The tenderized calcium fortified crackers and other baked goods of the present invention include calcium enriched reduced fat, low-fat, and no-fat baked products as well as conventional, full-fatted crackers and other baked goods which contain substantial amounts of ungelatinized starch. Dough lay times and dough machinability are not adversely affected, even though the doughs contain substantial amounts of calcium and even though their added fat level may be substantially reduced or completely eliminated.